If you are one who wants to buy a big pump,don't hot wire it in the conventional way. Leave the fuel pump wired as it is from the factory and tee into the 12 volt supply wire at the back of the fuel tank. Use a Hobbs switch to send voltage,through a wire connected to the generator,at a specific boost level when the motor can use the extra fuel.
Modifying stock fuel lines?
- Thread starter MNwe4
- Start date
Well Bison you were RIGHT and I was WRONG...the o-ring had a huge tear in it, I suppose when it was under higher than idle/vacuum fuel pressures it started to leak badly.
Guys, I must be honest although I've been modding cars for 16+ years and everything BUT this old Buick has been one of the harder cars I've ever worked on and I think it is just due to the age of the design and the age of the parts, even the aftermarket parts I have on my car (that came with it) are between 8-10 years old. I'm only 35 and my scope of car knowledge just doesn't cover some of the older technology used such as saginaw fittings and such in the fuel system.
Not making excuses here, just admitting at this point I am a true Buick novice..moving forward I think I'm going to check with the community before I do anything on this car and I hope I continue to get the support of my fellow Buick buddies.
Sheesh, well I've unplugged the 2nd pump (which I don't need with my little motor and turbo) and I doubt I'll have this problem again. Next weekend I should have the fuel pressure transducer, 3 bar AEM map all hooked up to the power logger for accurate data acquisition so hopefully I'll know the whole story regarding the fuel pressure rise under boost etc.
Guys, I must be honest although I've been modding cars for 16+ years and everything BUT this old Buick has been one of the harder cars I've ever worked on and I think it is just due to the age of the design and the age of the parts, even the aftermarket parts I have on my car (that came with it) are between 8-10 years old. I'm only 35 and my scope of car knowledge just doesn't cover some of the older technology used such as saginaw fittings and such in the fuel system.
Not making excuses here, just admitting at this point I am a true Buick novice..moving forward I think I'm going to check with the community before I do anything on this car and I hope I continue to get the support of my fellow Buick buddies. Sheesh, well I've unplugged the 2nd pump (which I don't need with my little motor and turbo) and I doubt I'll have this problem again. Next weekend I should have the fuel pressure transducer, 3 bar AEM map all hooked up to the power logger for accurate data acquisition so hopefully I'll know the whole story regarding the fuel pressure rise under boost etc.
Do you have a hotwire hooked to the fuel pumps?Well Bison you were RIGHT and I was WRONG...the o-ring had a huge tear in it, I suppose when it was under higher than idle/vacuum fuel pressures it started to leak badly.
Guys, I must be honest although I've been modding cars for 16+ years and everything BUT this old Buick has been one of the harder cars I've ever worked on and I think it is just due to the age of the design and the age of the parts, even the aftermarket parts I have on my car (that came with it) are between 8-10 years old. I'm only 35 and my scope of car knowledge just doesn't cover some of the older technology used such as saginaw fittings and such in the fuel system.
Sheesh, well I've unplugged the 2nd pump (which I don't need with my little motor and turbo) and I doubt I'll have this problem again. Next weekend I should have the fuel pressure transducer, 3 bar AEM map all hooked up to the power logger for accurate data acquisition so hopefully I'll know the whole story regarding the fuel pressure rise under boost etc.
If you unplug,it might get your idle pressure the rest of the way to 37-38lbs line on.
Then send the wire that activates the second pump,via a hobbs switch,to the 12 volt feed to the pump. Tee it in.
Badda boom,badda bing. Your pump speeds up when needed.
The best way to feed a motor is to send,only,the fuel that is needed and not a drop more.
Doing this will move you a step toward that perfect delivery method.
Well it doesn't appear the stock lines are going to work for me. Before we tried starting the car we jumped the pump at the back of the alternator and connector in the engine harness with the key in the on position. With the regulator all the way out the lowest it would go was 58 psi. The car only ran once for about 20 seconds and with the line on the regulator it barely dropped to 56 psi. I couldn't get it to fire up again. We pulled the plugs and they were soaked with fuel. For curiosity I'd like to check the voltage at the pump while running just to verify it's seeing 12 volts and that the boost-a-pump is not malfunctioning and supplying high voltage all the time. Otherwise I guess it's time for a -6 return line. Thoughts?
Did you drill the Saginaw fittings in the return line?
No we didn't drill out the lines, just hooked everything up to see where we were at. I believe it would help some, but probably not enough to get me down to where I'm comfortable with the adjustability.
Did you just follow Eric Marshall's method that you posted previously? The only thing I'm confused on is which fitting to put into the regulator. I know some people use 90 degree fittings, but I've heard that makes things a very tight fit and a 120 degree would be ideal. Would this fitting from Summit work?
http://www.summitracing.com/parts/FRA-491962-BL/
Then a 120 deg. hose end could be used from there. Just not sure what geometry is needed for the o-ring seal at the bottom of the regulator.
It's alive! With the battery outputting 12.6 volts the boost-a-pump was giving the fuel pump 15.3 volts. There was no way to adjust this down more, so we removed it from the car. With a normal alternator output around 13.7V my fuel pressure is now at 49 psi. It runs this way and the computer seems to be able to compensate, but you can tell it's really working at it. Fuel lines were not drilled. We're just going to install a new return line and have the adjustability we need.
northerngn
Master Monkeywrench
- Joined
- Oct 8, 2006
NICE!
Ok the parts for a new return line have been ordered, but I have another thought. Since the MSD booster was putting out too much voltage at idle I am now interested in why. The plan was to take it apart and hopefully find another potentiometer inside that could be turned down, but the instructions say it's potted so it's doubtful there is any solution there. What I think would be ideal with these newer pumps and stock lines is to have this booster provide something like 11 volts during idle and cruising and then up to 16ish under full boost. According to the literature, on its max setting it will add 2.7 volts at 5 psi and 10 volts at 30 psi, easily capable of the range I'm asking for. Even though the car is running with a hotwire kit now and a new return line will allow the fuel pressure to be reduced at idle and cruising, I am now concerned that I may run out of pump before I run out of injector.
My question is... does anybody know what I could add to the electrical circuit, before or after the box, to bring down the base voltage so that the pump sees less under normal conditions but still gets the jump when needed?
My question is... does anybody know what I could add to the electrical circuit, before or after the box, to bring down the base voltage so that the pump sees less under normal conditions but still gets the jump when needed?
You created this problem by buying the wrong pump.
It's the newest thing being pushed by this community and you fell for it.
You understand that less voltage would solve your problem,yet you have the pump hotwired.
Disconnect the hotwire and return the fuel pump wiring to stock. This will drop your idle fuel pressure even more.
Use a hobbs switch to activate the hotwire at whatever boost you would choose.
Tee the wire that comes from the generator,that the hotwire activates,into the fuel pump 12 volt supply wire back at the tank. Your pump will see the extra voltage when the hobbs switch activates the hotwire at boost when the return line will not be overwhelmed.
Use a hobbs switch to activate your fuel pump booster.
This might not get your idle fuel pressure down to what it should be,but drilling the two Saginaw fittings in the return line will.
You don't need to replace the return line.
After doing all this work you'll eventually run out of pump if you increase power enough.
You could have avoided all of this if you would have bought a doublepumper from Red Armstrong.
You're the latest in a long list of victims that this advise has burdened.
Wow, sorry for trying to think outside the box and come up with a few different options. I did not fall "victim" to trying one of the new fuel pumps. It was very clear that one of the consequences with running a larger pump was that a new return line would be needed. I thought there may be another solution and there probably is, just not with my current volt booster. After more testing tonight the minimum voltage it will put out is 15.3V, so it's no longer working as originally advertised and there's no way to fix it since all of the circuitry is potted. It still ramps up, but won't just pass through alternator voltage.
I will use a new return line as it's not that difficult and the car will run great. Eventually the limit of the equipment will be reached and more modifications can be done if necessary. That's the fun part of owing a project car. Thank you to everyone who shared their experiences and suggestions.
I will use a new return line as it's not that difficult and the car will run great. Eventually the limit of the equipment will be reached and more modifications can be done if necessary. That's the fun part of owing a project car. Thank you to everyone who shared their experiences and suggestions.
z
plug for a reds double pumper. who would have guessed...
stock car, reds double pumper
9 sec car, reds double pumper
reds double pumper for the win no matter what you have.
plug for a reds double pumper. who would have guessed...
stock car, reds double pumper
9 sec car, reds double pumper
reds double pumper for the win no matter what you have.
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